1. Field of the Invention
The present invention relates to an image forming apparatus, and more particularly an image forming apparatus capable of reproducing only a part from a frame of a video signal.
2. Description of the Prior Art
Conventional image forming apparatus generally prints out an entire frame even when only a part thereof is desired. There has therefore been desired an apparatus capable of printing only a part of a frame.
However, in case of printing only a principal object in the image signal of a frame in which said principal object is back lighted, the obtained image becomes generally dark and lacks tonal rendition. Such a situation occurs not only when the object is back lighted but also when the background contains brighter sky or objects of higher brightness, and the printed image shows satisfactory tonal rendition when the entire frame is printed but becomes dull when partially printed.